1. Field of the Invention
The present invention relates to compensation to reduce vibration in the drivetrain of a motor vehicle.
2. Description of the Related Art
In an electrically-propelled vehicle, a simple single-speed transmission can be used. Such a transmission can be used because, unlike an internal combustion engine, an electric motor can operate over a very wide rotational speed range. Thus, a multiple-speed transmission for converting from an internal combustion engine's relatively narrow speed range to a wider vehicle speed range is not necessary.
A single-speed transmission has several benefits, including simplicity, reliability and low cost. However, the gears of the transmission may be subject to "backlash", wherein the mating teeth of two gears (a driving gear and a driven gear) are not in contact when the driving gear begins to move. When such a backlash condition exists, the driving gear will accelerate quickly before its teeth are in contact with the teeth of the driven gear. The result can be a significant impact between the teeth of the gears when the teeth finally come into contact.
The impact can introduce a significant torsional oscillation into the vehicle's drivetrain, particularly at the drivetrain's torsional resonant frequency. The oscillation in turn can translate into customer dissatisfaction with the driveability of his vehicle.
Thus, a system which can reduce or eliminate backlash can improve customer satisfaction by reducing the resultant oscillation in the vehicle's drivetrain. Likewise, a system which can reduce the oscillation introduced by any backlash which may occur will also improve customer satisfaction.